diff --git a/scripts/download-using-manifests.pl.in b/scripts/download-using-manifests.pl.in
index 233d6a0437..2a383e49c4 100644
--- a/scripts/download-using-manifests.pl.in
+++ b/scripts/download-using-manifests.pl.in
@@ -15,6 +15,8 @@ my $tmpDir;
 do { $tmpDir = tmpnam(); }
 until mkdir $tmpDir, 0700;
 
+chdir $tmpDir or die "cannot change to `$tmpDir': $!";
+
 my $tmpNar = "$tmpDir/nar";
 my $tmpNar2 = "$tmpDir/nar2";